Techniques and apparatus for producing images at some wavelengths are lacking. The widespread successes of Fourier Transform Spectroscopy (FTS) methods in producing detailed spectra of weak sources are well known. [(See: Vanesse, G., ed. "Spectrometric Techniques I", Academic Press, New York (1977); Davis et al, Appl. Optics, 19, 4138-4155 (1980); Davis et al, Ap.J. 259, 166-179 (1982); Davis et al, Ap.J. 309, L95-L99 (1986); Larson et al, Ap. J. (Letters), 304, 481-489 (1986)] These successes have provided a stimulus for this effort to extend some of the advantages of the multiplexed FTS approach into the domains of imaging and imaging spectroscopy.
Prior art imaging devices using pixel-forming masks have not had high optical efficiency or have required large numbers of masks thereby reducing their usefulness.